1,876 research outputs found

    Flexible perceptual sensitivity to acoustic and distributional cues

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    Pronunciation variation in many ways is systematic, yielding patterns that a canny listener can exploit in order to aid perception. This work asks whether listeners actually do draw upon these patterns during speech perception. We focus in particular on a phenomenon known as paradigmatic enhancement, in which suffixes are phonetically enhanced in verbs which are frequent in their inflectional paradigms. In a set of four experiments, we found that listeners do not seem to attend to paradigmatic enhancement patterns. They do, however, attend to the distributional properties of a verb’s inflectional paradigm when the experimental task encourages attention to sublexical detail, as is the case with phoneme monitoring (Experiment 1a–b). When tasks require more holistic lexical processing, as with lexical decision (Experiment 2), the effect of paradigmatic probability disappears. If stimuli are presented in full sentences, such that the surrounding context provides richer contextual and semantic information (Experiment 3), even otherwise robust influences like lexical frequency disappear. We propose that these findings are consistent with a perceptual system that is flexible, and devotes processing resources to exploiting only those patterns that provide a sufficient cognitive return on investment

    Generating patterns on clothing for seamless design

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    Symmetric patterns are used widely in clothing manufacture. However, the discontinuity of patterns at seams can disrupt the visual appeal of clothing. While it is possible to align patterns to conceal such pattern breaks, it is hard create a completely seamless garment in terms of pattern continuity. In this thesis, we explore computational methods to parameterize the clothing pieces relative to a pattern’s coordinate system to achieve pattern continuity over garments. We review previous work related to pattern alignment on clothing. We also review surface quadrangulation methods. With a suitable quadrangulation, we can map any planar pattern with fourfold rotations into each quad, and achieve a seamless design. With an understanding of previous work, we approached the problems from three angles. First, we mapped patterns with sixfold rotations onto clothing by triangulating the clothing pieces and ensuring consistency of triangle vertices on both sides of a seam. We also mapped patterns with fourfold rotations onto clothing by optimizing the shape of each clothing piece in the texture domain. Lastly, we performed quadrangulation guided by cross fields, and mapped fourfold pattern units into each quad. We assembled and simulated the texture mapped clothing in Blender to visualize the results

    Uncertainty in Climate Change Projections of the Hadley Circulation: The Role of Internal Variability

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    The uncertainty arising from internal climate variability in climate change projections of the Hadley circulation (HC) is presently unknown. In this paper it is quantified by analyzing a 40-member ensemble of integrations of the Community Climate System Model, version 3 (CCSM3), under the Special Report on Emissions Scenarios (SRES) A1B scenario over the period 2000–60. An additional set of 100-yr-long time-slice integrations with the atmospheric component of the same model [Community Atmosphere Model, version 3.0 (CAM3)] is also analyzed. Focusing on simple metrics of the HC—its strength, width, and height—three key results emerge from the analysis of the CCSM3 ensemble. First, the projected weakening of the HC is almost entirely confined to the Northern Hemisphere, and is stronger in winter than in summer. Second, the projected widening of the HC occurs only in the winter season but in both hemispheres. Third, the projected rise of the tropical tropopause occurs in both hemispheres and in all seasons and is, by far, the most robust of the three metrics. This paper shows further that uncertainty in future trends of the HC width is largely controlled by extratropical variability, while those of HC strength and height are associated primarily with tropical dynamics. Comparison of the CCSM3 and CAM3 integrations reveals that ocean–atmosphere coupling is the dominant source of uncertainty in future trends of HC strength and height and of the tropical mean meridional circulation in general. Finally, uncertainty in future trends of the hydrological cycle is largely captured by the uncertainty in future trends of the mean meridional circulation

    Extratropical???Tropical Interaction Model Intercomparison Project (Etin-Mip): Protocol and Initial Results

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    This article introduces the Extratropical???Tropical Interaction Model Intercomparison Project (ETIN-MIP), where a set of fully coupled model experiments are designed to examine the sources of longstanding tropical precipitation biases in climate models. In particular, we reduce insolation over three targeted latitudinal bands of persistent model biases: the southern extratropics, the southern tropics, and the northern extratropics. To address the effect of regional energy bias corrections on the mean distribution of tropical precipitation, such as the double intertropical convergence zone problem, we evaluate the quasi-equilibrium response of the climate system corresponding to a 50-yr period after the 100 years of prescribed energy perturbation. Initial results show that, despite a large intermodel spread in each perturbation experiment due to differences in ocean heat uptake response and climate feedbacks across models, the southern tropics is most efficient at driving a meridional shift of tropical precipitation. In contrast, the extratropical energy perturbations are effectively damped by anomalous heat uptake over the subpolar oceans, thereby inducing a smaller meridional shift of tropical precipitation compared with the tropical energy perturbations. The ETIN-MIP experiments allow us to investigate the global implications of regional energy bias corrections, providing a route to guide the practice of model development, with implications for understanding dynamical responses to anthropogenic climate change and geoengineering

    Correlation-induced insulating topological phases at charge neutrality in twisted bilayer graphene

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    Twisted bilayer graphene (TBG) provides a unique framework to elucidate the interplay between strong correlations and topological phenomena in two-dimensional systems. The existence of multiple electronic degrees of freedom -- charge, spin, and valley -- gives rise to a plethora of possible ordered states and instabilities. Identifying which of them are realized in the regime of strong correlations is fundamental to shed light on the nature of the superconducting and correlated insulating states observed in the TBG experiments. Here, we use unbiased, sign-problem-free quantum Monte Carlo simulations to solve an effective interacting lattice model for TBG at charge neutrality. Besides the usual cluster Hubbard-like repulsion, this model also contains an assisted hopping interaction that emerges due to the non-trivial topological properties of TBG. Such a non-local interaction fundamentally alters the phase diagram at charge neutrality, gapping the Dirac cones even for infinitesimally small interaction. As the interaction strength increases, a sequence of different correlated insulating phases emerge, including a quantum valley Hall state with topological edge states, an intervalley-coherent insulator, and a valence bond solid. The charge-neutrality correlated insulating phases discovered here provide the sought-after reference states needed for a comprehensive understanding of the insulating states at integer fillings and the proximate superconducting states of TBG.Comment: 15 pages, 9 figures, 2 table

    Using the Utah Population Database to assess familial risk of primary open angle glaucoma

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    AbstractPurposePrimary open angle glaucoma (POAG) is a leading cause of irreversible blindness in the elderly. Previous epidemiological studies have identified family history, ethnic origin, age, high intraocular pressure and diabetes mellitus as risk factors. However, it is difficult to assess the extent family history plays in this disease process. The Utah Population Database (UPDB), created by the University of Utah, has recently become a resource for which greater than 9 million records are available for use. The UPDB is divided into two major data sets from which family members can be identified, namely 1.6 million genealogy records and 2 million Utah birth certificates. This study utilizes these resources to assess the familial risk of POAG within the Utah Population.MethodsThe University of Utah’s hospital and clinic records were searched for patients with primary and chronic open angle glaucoma (ICD9 codes 365.04 and 365.11) between the years 1995 and 2005. A case-control analysis was then performed with specialized UPDB software that was modified to constrain the control and pedigree populations to over 1 million University of Utah-UPDB linked records. Controls were matched to cases by gender and birth year (±2.5years) with only one control being used per case. Population-attributable risk (PAR) to familial factors and relative risk (RR) were computed using conditional logistic regression (CLR).ResultsFrom the original 1.5 million medical records, 6198 patients with glaucoma were identified. Of these, 3391 met the inclusion criteria, which required patients to have at least one parent or one child in the UPDB. The PAR in this population was found to be 0.20, indicating 20% of the risk for glaucoma is attributable to genetic factors. CLR computations also showed a significantly increased relative risk (p<0.05) in first cousins (RR=1.45 (95% confidence interval (CI) 1.16–1.8)), second cousins (RR=1.19 (95% CI 1.08–1.32)), siblings (RR=3.76 (95% CI 2.66–5.31)), parents (RR=6.25 (95% CI 3.94–9.9)) and children (RR=6.77 (95% CI 3.39–13.5)).ConclusionsBased on these familial data, there is a significantly higher prevalence of glaucoma in both first and second generation relatives of those affected as compared to relatives in the control group. When compared with other epidemiologic studies, such as an analysis of first-degree relatives of patients from the Rotterdam study, which showed a PAR of 16%, our study actually demonstrates a greater familial contribution to glaucoma. The UPDB is a valuable and unique resource providing a large population from which to analyze the familial risk of glaucoma

    Melt Property Variation In GeSe2-As2Se3-PbSe Glass Ceramics For Infrared Gradient Refractive Index (GRIN) Applications

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    Melt size-dependent physical property variation is examined in a multicomponent GeSe2-As2Se3-PbSe chalcogenide glass developed for gradient refractive index applications. The impact of melting conditions on small (40 g) prototype laboratory-scale melts extended to commercially relevant melt sizes (1.325 kg) have been studied and the role of thermal history variation on physical and optical property evolution in parent glass, the glass\u27 crystallization behavior and post heat-treated glass ceramics, is quantified. As-melted glass morphology, optical homogeneity and heat treatment-induced microstructure following a fixed, two-step nucleation and growth protocol exhibit marked variation with melt size. These attributes are shown to impact crystallization behavior (growth rates, resulting crystalline phase formation) and induced effective refractive index change, neff, in the resulting optical nanocomposite. The magnitude of these changes is discussed based on thermal history related melt conditions
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